I’ve been studying pikas, little rabbit cousins, for over 50 years, and I don’t get tired of looking at them. These tailless egg-shaped fluff balls live mainly in mountainous and cold environments, in piles of broken rock, called slopes.
During the summer, observers can see picas that collect industrially hidden grass and leaves in haystacks that will serve as a food supply during the winter. Their light brown coats blend well with their surroundings, making them easier to spot when placed on prominent rocks and screaming to alert other pikes of their presence.
When other hikers see me watching pikas in the Sierra Nevada, California, they often tell me that they have read that these animals become extinct. I’ve collected a stack of press releases that say exactly that. But, based on my recent research and a thorough review of more than 100 peer-reviewed studies, I find this interpretation misleading.
Limited by climate
As I demonstrated in my early research, the biology of pikas suggests that they are likely to be affected by a warming climate. Most importantly, your normal body temperature is high, which poses a risk of overheating when active in warm environments. When temperatures are warm, sinks retreat to much cooler depths of their talus habitat.
Temperature also plays a role in the ability of pikas to move from one place to another. The warm climate inhibits their movements, while colder temperatures allow them to colonize new habitats more freely.
A bit of ancient history is instructive here. Pikas originally came to North America from Asia and spread across the continent about five million years ago, in colder times. His remains have been found in the caves of the Appalachian Mountains and in the Mojave Desert, places where pikas no longer live.
American pike live mainly in alpine and subalpine mountainous areas that extend south from central British Columbia and Alberta to the Rocky Mountains of New Mexico and the Sierra Nevada of California. Andrew Smith, CC BY-ND
As the global climate warmed, pika populations retreated to the high mountains of the western U.S. and Canada. Today they occupy most of the available logging habitat in these areas, evidence that challenges the pikas narrative.
For example, in recent surveys, pikas were found at 98% of the 109 suitable sites in Colorado and 98% of the 329 sites in the central Sierra Nevada. A study of historic pika sites across California’s national parks, Lassen, Yosemite, Kings Canyon, and Sequoia, found no evidence that pikas moved to new locations or higher altitudes due to climate change.
Pikes in warm environments
In contrast, most places where researchers believe pikas have disappeared are small, isolated, and often compromised by human activities, such as grazing livestock. These sites are generally lower and warmer than the sites in the central range of pikas.
Many of these areas are located in the Great Basin, a large desert region that covers most of Nevada and parts of Utah, Idaho, Wyoming, Oregon and California. A number of studies on a small number of marginal sites in the Great Basin previously occupied by pikas have disproportionately contributed to the narrative that pikas are likely to be endangered.
To investigate the overall picture of this region, I worked with state and federal officials in a 2017 study that identified 3,250 pika habitat records. Pika were present at 2,378 sites, were not found at 89 sites where they had been seen recently in 2005, and absent from 774 sites containing only ancient signs of pika occupation.
The old, uprooted places had the same temperature and precipitation ranges as the places where there were still pikas. This suggests that non-climatic factors may have caused pikas to disappear from vacant sites.
The pika have disappeared from some parts of the Great Basin, but climate change may not be the cause. Kmusser / Wikipedia, CC BY-S
Pikas are still present in other very hot places, such as the ghost town of Bodie, California, the nearby Mono Craters, and the Idaho Moon Crater National Monument. In these places, pikas are removed to cool corners of their talus habitat during the warmest part of the day and are often eaten at night.
In my research, I also found that pikas were much less active and uttered far fewer calls at these low-altitude sites compared to high-elevation pika populations. At low elevation sites, pikas consumed a diverse diet of Great Basin plants, such as sagebrush and bitterbrush, which was markedly different from the plants they ate at high elevation sites. Some did not even manage to build their large characteristic hayfields.
Another atypical pika population lives near sea level in the Columbia River Gorge in Oregon. Here too they have adapted well to a very different habitat, surviving all year round with a diet consisting mainly of moss. They defend the smallest territories from any pika and, when it is hot, they simply move away from the slope and stay in the shade of the nearby forest.
A future for Pikas
According to my review of dozens of studies, pika populations appear to be safe in their distribution core: the mountains of western North America that have a large, fairly well-connected talus habitat. In these areas they can move from one habitat plot to another without having to go through dangerously warm areas for them.
The fact that pikes have also adapted to various marginal and warm environments suggests to me that they are more resistant to climate change than many past studies have concluded. Most species have losses near the edges of their geographical areas, simply because individual animals in these areas live in conditions less than ideal for them. That doesn’t mean they become extinct.
Climate change is the most critical issue facing the world today, so it is particularly important that scientists communicate accurately to the public. In my opinion, the fact that pikas cope and alter their behaviors in response to changing conditions is encouraging news for future naturalists who set out to observe one of nature’s most charismatic mammals.
Andrew Smith is Professor Emeritus of Life Sciences at Arizona State University.
Disclosure Statement: Andrew Smith does not work, consult, share, or receive funding from any company or organization that may benefit from this article, and has not disclosed any relevant affiliation beyond his or her academic appointment.
It is republished with permission from The Conversation.
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